diff --git a/ChangeLog b/ChangeLog
index ae8d86f..c94218e 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -9,6 +9,12 @@
      a non DER-compliant certificate correctly signed by a trusted CA, or a
      trusted CA with a non DER-compliant certificate. Found by luocm on GitHub.
      Fixes #825.
+   * Fix buffer length assertion in the ssl_parse_certificate_request()
+     function which leads to an arbitrary overread of the message buffer. The
+     overreads could occur upon receiving a message malformed at the point
+     where an optional signature algorithms list is expected in the cases of
+     the signature algorithms section being too short. In the debug builds
+     the overread data is printed to the standard output.
 
 Features
    * Add option MBEDTLS_AES_FEWER_TABLES to dynamically compute 3/4 of the AES tables
@@ -55,6 +61,9 @@
      in the internal buffers; these cases lead to deadlocks in case
      event-driven I/O was used.
      Found and reported by Hubert Mis in #772.
+   * Fix buffer length assertions in the ssl_parse_certificate_request()
+     function which leads to a potential one byte overread of the message
+     buffer.
 
 Changes
    * Remove some redundant code in bignum.c. Contributed by Alexey Skalozub.
@@ -95,6 +104,11 @@
      by Jiayuan Chen in #1377. Fixes #1437.
    * Improve security of RSA key generation by including criteria from FIPS
      186-4. Contributed by Jethro Beekman. #1380
+   * Declare functions in header files even when an alternative implementation
+     of the corresponding module is activated by defining the corresponding
+     MBEDTLS_XXX_ALT macro. This means that alternative implementations do
+     not need to copy the declarations, and ensures that they will have the
+     same API.
 
 = mbed TLS 2.8.0 branch released 2018-03-16
 
diff --git a/include/mbedtls/aes.h b/include/mbedtls/aes.h
index 3c5b133..e0fc238 100644
--- a/include/mbedtls/aes.h
+++ b/include/mbedtls/aes.h
@@ -62,14 +62,14 @@
 #define inline __inline
 #endif
 
-#if !defined(MBEDTLS_AES_ALT)
-// Regular implementation
-//
-
 #ifdef __cplusplus
 extern "C" {
 #endif
 
+#if !defined(MBEDTLS_AES_ALT)
+// Regular implementation
+//
+
 /**
  * \brief The AES context-type definition.
  */
@@ -88,6 +88,10 @@
 }
 mbedtls_aes_context;
 
+#else  /* MBEDTLS_AES_ALT */
+#include "aes_alt.h"
+#endif /* MBEDTLS_AES_ALT */
+
 /**
  * \brief          This function initializes the specified AES context.
  *
@@ -396,18 +400,6 @@
 #undef MBEDTLS_DEPRECATED
 #endif /* !MBEDTLS_DEPRECATED_REMOVED */
 
-#ifdef __cplusplus
-}
-#endif
-
-#else  /* MBEDTLS_AES_ALT */
-#include "aes_alt.h"
-#endif /* MBEDTLS_AES_ALT */
-
-#ifdef __cplusplus
-extern "C" {
-#endif
-
 /**
  * \brief          Checkup routine.
  *
diff --git a/include/mbedtls/arc4.h b/include/mbedtls/arc4.h
index f9d93f8..f11fc5b 100644
--- a/include/mbedtls/arc4.h
+++ b/include/mbedtls/arc4.h
@@ -38,14 +38,14 @@
 
 #define MBEDTLS_ERR_ARC4_HW_ACCEL_FAILED                  -0x0019  /**< ARC4 hardware accelerator failed. */
 
-#if !defined(MBEDTLS_ARC4_ALT)
-// Regular implementation
-//
-
 #ifdef __cplusplus
 extern "C" {
 #endif
 
+#if !defined(MBEDTLS_ARC4_ALT)
+// Regular implementation
+//
+
 /**
  * \brief     ARC4 context structure
  *
@@ -61,6 +61,10 @@
 }
 mbedtls_arc4_context;
 
+#else  /* MBEDTLS_ARC4_ALT */
+#include "arc4_alt.h"
+#endif /* MBEDTLS_ARC4_ALT */
+
 /**
  * \brief          Initialize ARC4 context
  *
@@ -118,18 +122,6 @@
 int mbedtls_arc4_crypt( mbedtls_arc4_context *ctx, size_t length, const unsigned char *input,
                 unsigned char *output );
 
-#ifdef __cplusplus
-}
-#endif
-
-#else  /* MBEDTLS_ARC4_ALT */
-#include "arc4_alt.h"
-#endif /* MBEDTLS_ARC4_ALT */
-
-#ifdef __cplusplus
-extern "C" {
-#endif
-
 /**
  * \brief          Checkup routine
  *
diff --git a/include/mbedtls/blowfish.h b/include/mbedtls/blowfish.h
index c0ef5a0..22479be 100644
--- a/include/mbedtls/blowfish.h
+++ b/include/mbedtls/blowfish.h
@@ -44,14 +44,14 @@
 #define MBEDTLS_ERR_BLOWFISH_HW_ACCEL_FAILED                   -0x0017  /**< Blowfish hardware accelerator failed. */
 #define MBEDTLS_ERR_BLOWFISH_INVALID_INPUT_LENGTH              -0x0018  /**< Invalid data input length. */
 
-#if !defined(MBEDTLS_BLOWFISH_ALT)
-// Regular implementation
-//
-
 #ifdef __cplusplus
 extern "C" {
 #endif
 
+#if !defined(MBEDTLS_BLOWFISH_ALT)
+// Regular implementation
+//
+
 /**
  * \brief          Blowfish context structure
  */
@@ -62,6 +62,10 @@
 }
 mbedtls_blowfish_context;
 
+#else  /* MBEDTLS_BLOWFISH_ALT */
+#include "blowfish_alt.h"
+#endif /* MBEDTLS_BLOWFISH_ALT */
+
 /**
  * \brief          Initialize Blowfish context
  *
@@ -198,8 +202,4 @@
 }
 #endif
 
-#else  /* MBEDTLS_BLOWFISH_ALT */
-#include "blowfish_alt.h"
-#endif /* MBEDTLS_BLOWFISH_ALT */
-
 #endif /* blowfish.h */
diff --git a/include/mbedtls/camellia.h b/include/mbedtls/camellia.h
index cf07629..f0466bf 100644
--- a/include/mbedtls/camellia.h
+++ b/include/mbedtls/camellia.h
@@ -40,14 +40,14 @@
 #define MBEDTLS_ERR_CAMELLIA_INVALID_INPUT_LENGTH         -0x0026  /**< Invalid data input length. */
 #define MBEDTLS_ERR_CAMELLIA_HW_ACCEL_FAILED              -0x0027  /**< Camellia hardware accelerator failed. */
 
-#if !defined(MBEDTLS_CAMELLIA_ALT)
-// Regular implementation
-//
-
 #ifdef __cplusplus
 extern "C" {
 #endif
 
+#if !defined(MBEDTLS_CAMELLIA_ALT)
+// Regular implementation
+//
+
 /**
  * \brief          CAMELLIA context structure
  */
@@ -58,6 +58,10 @@
 }
 mbedtls_camellia_context;
 
+#else  /* MBEDTLS_CAMELLIA_ALT */
+#include "camellia_alt.h"
+#endif /* MBEDTLS_CAMELLIA_ALT */
+
 /**
  * \brief          Initialize CAMELLIA context
  *
@@ -211,18 +215,6 @@
                        unsigned char *output );
 #endif /* MBEDTLS_CIPHER_MODE_CTR */
 
-#ifdef __cplusplus
-}
-#endif
-
-#else  /* MBEDTLS_CAMELLIA_ALT */
-#include "camellia_alt.h"
-#endif /* MBEDTLS_CAMELLIA_ALT */
-
-#ifdef __cplusplus
-extern "C" {
-#endif
-
 /**
  * \brief          Checkup routine
  *
diff --git a/include/mbedtls/ccm.h b/include/mbedtls/ccm.h
index 5a34f3a..8585ce5 100644
--- a/include/mbedtls/ccm.h
+++ b/include/mbedtls/ccm.h
@@ -43,14 +43,15 @@
 #define MBEDTLS_ERR_CCM_AUTH_FAILED     -0x000F /**< Authenticated decryption failed. */
 #define MBEDTLS_ERR_CCM_HW_ACCEL_FAILED -0x0011 /**< CCM hardware accelerator failed. */
 
-#if !defined(MBEDTLS_CCM_ALT)
-// Regular implementation
-//
 
 #ifdef __cplusplus
 extern "C" {
 #endif
 
+#if !defined(MBEDTLS_CCM_ALT)
+// Regular implementation
+//
+
 /**
  * \brief    The CCM context-type definition. The CCM context is passed
  *           to the APIs called.
@@ -60,6 +61,10 @@
 }
 mbedtls_ccm_context;
 
+#else  /* MBEDTLS_CCM_ALT */
+#include "ccm_alt.h"
+#endif /* MBEDTLS_CCM_ALT */
+
 /**
  * \brief           This function initializes the specified CCM context,
  *                  to make references valid, and prepare the context
@@ -155,17 +160,6 @@
                       const unsigned char *input, unsigned char *output,
                       const unsigned char *tag, size_t tag_len );
 
-#ifdef __cplusplus
-}
-#endif
-
-#else  /* MBEDTLS_CCM_ALT */
-#include "ccm_alt.h"
-#endif /* MBEDTLS_CCM_ALT */
-
-#ifdef __cplusplus
-extern "C" {
-#endif
 
 #if defined(MBEDTLS_SELF_TEST) && defined(MBEDTLS_AES_C)
 /**
diff --git a/include/mbedtls/cmac.h b/include/mbedtls/cmac.h
index 0ada742..913c05f 100644
--- a/include/mbedtls/cmac.h
+++ b/include/mbedtls/cmac.h
@@ -63,6 +63,10 @@
     size_t              unprocessed_len;
 };
 
+#else  /* !MBEDTLS_CMAC_ALT */
+#include "cmac_alt.h"
+#endif /* !MBEDTLS_CMAC_ALT */
+
 /**
  * \brief               This function sets the CMAC key, and prepares to authenticate
  *                      the input data.
@@ -185,18 +189,6 @@
                               unsigned char output[16] );
 #endif /* MBEDTLS_AES_C */
 
-#ifdef __cplusplus
-}
-#endif
-
-#else  /* !MBEDTLS_CMAC_ALT */
-#include "cmac_alt.h"
-#endif /* !MBEDTLS_CMAC_ALT */
-
-#ifdef __cplusplus
-extern "C" {
-#endif
-
 #if defined(MBEDTLS_SELF_TEST) && ( defined(MBEDTLS_AES_C) || defined(MBEDTLS_DES_C) )
 /**
  * \brief          The CMAC checkup routine.
diff --git a/include/mbedtls/des.h b/include/mbedtls/des.h
index 5a1a636..6eb7d03 100644
--- a/include/mbedtls/des.h
+++ b/include/mbedtls/des.h
@@ -46,14 +46,14 @@
 
 #define MBEDTLS_DES_KEY_SIZE    8
 
-#if !defined(MBEDTLS_DES_ALT)
-// Regular implementation
-//
-
 #ifdef __cplusplus
 extern "C" {
 #endif
 
+#if !defined(MBEDTLS_DES_ALT)
+// Regular implementation
+//
+
 /**
  * \brief          DES context structure
  *
@@ -76,6 +76,10 @@
 }
 mbedtls_des3_context;
 
+#else  /* MBEDTLS_DES_ALT */
+#include "des_alt.h"
+#endif /* MBEDTLS_DES_ALT */
+
 /**
  * \brief          Initialize DES context
  *
@@ -331,17 +335,6 @@
  */
 void mbedtls_des_setkey( uint32_t SK[32],
                          const unsigned char key[MBEDTLS_DES_KEY_SIZE] );
-#ifdef __cplusplus
-}
-#endif
-
-#else  /* MBEDTLS_DES_ALT */
-#include "des_alt.h"
-#endif /* MBEDTLS_DES_ALT */
-
-#ifdef __cplusplus
-extern "C" {
-#endif
 
 /**
  * \brief          Checkup routine
diff --git a/include/mbedtls/dhm.h b/include/mbedtls/dhm.h
index b3b3761..f848e22 100644
--- a/include/mbedtls/dhm.h
+++ b/include/mbedtls/dhm.h
@@ -71,7 +71,6 @@
 #include MBEDTLS_CONFIG_FILE
 #endif
 #include "bignum.h"
-#if !defined(MBEDTLS_DHM_ALT)
 
 /*
  * DHM Error codes
@@ -92,6 +91,8 @@
 extern "C" {
 #endif
 
+#if !defined(MBEDTLS_DHM_ALT)
+
 /**
  * \brief          The DHM context structure.
  */
@@ -111,6 +112,10 @@
 }
 mbedtls_dhm_context;
 
+#else /* MBEDTLS_DHM_ALT */
+#include "dhm_alt.h"
+#endif /* MBEDTLS_DHM_ALT */
+
 /**
  * \brief          This function initializes the DHM context.
  *
@@ -290,18 +295,6 @@
 #endif /* MBEDTLS_FS_IO */
 #endif /* MBEDTLS_ASN1_PARSE_C */
 
-#ifdef __cplusplus
-}
-#endif
-
-#else /* MBEDTLS_DHM_ALT */
-#include "dhm_alt.h"
-#endif /* MBEDTLS_DHM_ALT */
-
-#ifdef __cplusplus
-extern "C" {
-#endif
-
 /**
  * \brief          The DMH checkup routine.
  *
diff --git a/include/mbedtls/ecjpake.h b/include/mbedtls/ecjpake.h
index d86e820..cc2b316 100644
--- a/include/mbedtls/ecjpake.h
+++ b/include/mbedtls/ecjpake.h
@@ -44,8 +44,6 @@
 #include "ecp.h"
 #include "md.h"
 
-#if !defined(MBEDTLS_ECJPAKE_ALT)
-
 #ifdef __cplusplus
 extern "C" {
 #endif
@@ -58,6 +56,7 @@
     MBEDTLS_ECJPAKE_SERVER,             /**< Server                         */
 } mbedtls_ecjpake_role;
 
+#if !defined(MBEDTLS_ECJPAKE_ALT)
 /**
  * EC J-PAKE context structure.
  *
@@ -88,6 +87,10 @@
     mbedtls_mpi s;                      /**< Pre-shared secret (passphrase) */
 } mbedtls_ecjpake_context;
 
+#else  /* MBEDTLS_ECJPAKE_ALT */
+#include "ecjpake_alt.h"
+#endif /* MBEDTLS_ECJPAKE_ALT */
+
 /**
  * \brief           Initialize a context
  *                  (just makes it ready for setup() or free()).
@@ -225,20 +228,10 @@
  */
 void mbedtls_ecjpake_free( mbedtls_ecjpake_context *ctx );
 
-#ifdef __cplusplus
-}
-#endif
 
-#else  /* MBEDTLS_ECJPAKE_ALT */
-#include "ecjpake_alt.h"
-#endif /* MBEDTLS_ECJPAKE_ALT */
 
 #if defined(MBEDTLS_SELF_TEST)
 
-#ifdef __cplusplus
-extern "C" {
-#endif
-
 /**
  * \brief          Checkup routine
  *
@@ -246,10 +239,11 @@
  */
 int mbedtls_ecjpake_self_test( int verbose );
 
+#endif /* MBEDTLS_SELF_TEST */
+
 #ifdef __cplusplus
 }
 #endif
 
-#endif /* MBEDTLS_SELF_TEST */
 
 #endif /* ecjpake.h */
diff --git a/include/mbedtls/ecp.h b/include/mbedtls/ecp.h
index 9fc650e..3ad74e6 100644
--- a/include/mbedtls/ecp.h
+++ b/include/mbedtls/ecp.h
@@ -51,15 +51,6 @@
 #define MBEDTLS_ERR_ECP_SIG_LEN_MISMATCH                  -0x4C00  /**< The buffer contains a valid signature followed by more data. */
 #define MBEDTLS_ERR_ECP_HW_ACCEL_FAILED                   -0x4B80  /**< The ECP hardware accelerator failed. */
 
-#if !defined(MBEDTLS_ECP_ALT)
-/*
- * default mbed TLS elliptic curve arithmetic implementation
- *
- * (in case MBEDTLS_ECP_ALT is defined then the developer has to provide an
- * alternative implementation for the whole module and it will replace this
- * one.)
- */
-
 #ifdef __cplusplus
 extern "C" {
 #endif
@@ -128,6 +119,15 @@
 }
 mbedtls_ecp_point;
 
+#if !defined(MBEDTLS_ECP_ALT)
+/*
+ * default mbed TLS elliptic curve arithmetic implementation
+ *
+ * (in case MBEDTLS_ECP_ALT is defined then the developer has to provide an
+ * alternative implementation for the whole module and it will replace this
+ * one.)
+ */
+
 /**
  * \brief           The ECP group structure.
  *
@@ -182,22 +182,6 @@
 mbedtls_ecp_group;
 
 /**
- * \brief    The ECP key-pair structure.
- *
- * A generic key-pair that may be used for ECDSA and fixed ECDH, for example.
- *
- * \note    Members are deliberately in the same order as in the
- *          ::mbedtls_ecdsa_context structure.
- */
-typedef struct
-{
-    mbedtls_ecp_group grp;      /*!<  The elliptic curve and base point. */
-    mbedtls_mpi d;              /*!<  Our secret value. */
-    mbedtls_ecp_point Q;        /*!<  Our public value. */
-}
-mbedtls_ecp_keypair;
-
-/**
  * \name SECTION: Module settings
  *
  * The configuration options you can set for this module are in this section.
@@ -255,6 +239,26 @@
 
 /* \} name SECTION: Module settings */
 
+#else  /* MBEDTLS_ECP_ALT */
+#include "ecp_alt.h"
+#endif /* MBEDTLS_ECP_ALT */
+
+/**
+ * \brief    The ECP key-pair structure.
+ *
+ * A generic key-pair that may be used for ECDSA and fixed ECDH, for example.
+ *
+ * \note    Members are deliberately in the same order as in the
+ *          ::mbedtls_ecdsa_context structure.
+ */
+typedef struct
+{
+    mbedtls_ecp_group grp;      /*!<  Elliptic curve and base point     */
+    mbedtls_mpi d;              /*!<  our secret value                  */
+    mbedtls_ecp_point Q;        /*!<  our public value                  */
+}
+mbedtls_ecp_keypair;
+
 /*
  * Point formats, from RFC 4492's enum ECPointFormat
  */
@@ -757,8 +761,4 @@
 }
 #endif
 
-#else  /* MBEDTLS_ECP_ALT */
-#include "ecp_alt.h"
-#endif /* MBEDTLS_ECP_ALT */
-
 #endif /* ecp.h */
diff --git a/include/mbedtls/gcm.h b/include/mbedtls/gcm.h
index 119e275..3c22033 100644
--- a/include/mbedtls/gcm.h
+++ b/include/mbedtls/gcm.h
@@ -44,12 +44,12 @@
 #define MBEDTLS_ERR_GCM_HW_ACCEL_FAILED                   -0x0013  /**< GCM hardware accelerator failed. */
 #define MBEDTLS_ERR_GCM_BAD_INPUT                         -0x0014  /**< Bad input parameters to function. */
 
-#if !defined(MBEDTLS_GCM_ALT)
-
 #ifdef __cplusplus
 extern "C" {
 #endif
 
+#if !defined(MBEDTLS_GCM_ALT)
+
 /**
  * \brief          The GCM context structure.
  */
@@ -68,6 +68,10 @@
 }
 mbedtls_gcm_context;
 
+#else  /* !MBEDTLS_GCM_ALT */
+#include "gcm_alt.h"
+#endif /* !MBEDTLS_GCM_ALT */
+
 /**
  * \brief           This function initializes the specified GCM context,
  *                  to make references valid, and prepares the context
@@ -246,18 +250,6 @@
  */
 void mbedtls_gcm_free( mbedtls_gcm_context *ctx );
 
-#ifdef __cplusplus
-}
-#endif
-
-#else  /* !MBEDTLS_GCM_ALT */
-#include "gcm_alt.h"
-#endif /* !MBEDTLS_GCM_ALT */
-
-#ifdef __cplusplus
-extern "C" {
-#endif
-
 /**
  * \brief          The GCM checkup routine.
  *
diff --git a/include/mbedtls/md2.h b/include/mbedtls/md2.h
index 0fd8b5a..08e75b2 100644
--- a/include/mbedtls/md2.h
+++ b/include/mbedtls/md2.h
@@ -39,14 +39,14 @@
 
 #define MBEDTLS_ERR_MD2_HW_ACCEL_FAILED                   -0x002B  /**< MD2 hardware accelerator failed */
 
-#if !defined(MBEDTLS_MD2_ALT)
-// Regular implementation
-//
-
 #ifdef __cplusplus
 extern "C" {
 #endif
 
+#if !defined(MBEDTLS_MD2_ALT)
+// Regular implementation
+//
+
 /**
  * \brief          MD2 context structure
  *
@@ -64,6 +64,10 @@
 }
 mbedtls_md2_context;
 
+#else  /* MBEDTLS_MD2_ALT */
+#include "md2_alt.h"
+#endif /* MBEDTLS_MD2_ALT */
+
 /**
  * \brief          Initialize MD2 context
  *
@@ -235,18 +239,6 @@
 #undef MBEDTLS_DEPRECATED
 #endif /* !MBEDTLS_DEPRECATED_REMOVED */
 
-#ifdef __cplusplus
-}
-#endif
-
-#else  /* MBEDTLS_MD2_ALT */
-#include "md2_alt.h"
-#endif /* MBEDTLS_MD2_ALT */
-
-#ifdef __cplusplus
-extern "C" {
-#endif
-
 /**
  * \brief          Output = MD2( input buffer )
  *
diff --git a/include/mbedtls/md4.h b/include/mbedtls/md4.h
index 23fa95e..8ee4e5c 100644
--- a/include/mbedtls/md4.h
+++ b/include/mbedtls/md4.h
@@ -40,14 +40,14 @@
 
 #define MBEDTLS_ERR_MD4_HW_ACCEL_FAILED                   -0x002D  /**< MD4 hardware accelerator failed */
 
-#if !defined(MBEDTLS_MD4_ALT)
-// Regular implementation
-//
-
 #ifdef __cplusplus
 extern "C" {
 #endif
 
+#if !defined(MBEDTLS_MD4_ALT)
+// Regular implementation
+//
+
 /**
  * \brief          MD4 context structure
  *
@@ -64,6 +64,10 @@
 }
 mbedtls_md4_context;
 
+#else  /* MBEDTLS_MD4_ALT */
+#include "md4_alt.h"
+#endif /* MBEDTLS_MD4_ALT */
+
 /**
  * \brief          Initialize MD4 context
  *
@@ -238,18 +242,6 @@
 #undef MBEDTLS_DEPRECATED
 #endif /* !MBEDTLS_DEPRECATED_REMOVED */
 
-#ifdef __cplusplus
-}
-#endif
-
-#else  /* MBEDTLS_MD4_ALT */
-#include "md4_alt.h"
-#endif /* MBEDTLS_MD4_ALT */
-
-#ifdef __cplusplus
-extern "C" {
-#endif
-
 /**
  * \brief          Output = MD4( input buffer )
  *
diff --git a/include/mbedtls/md5.h b/include/mbedtls/md5.h
index 06ea4c5..43ead4b 100644
--- a/include/mbedtls/md5.h
+++ b/include/mbedtls/md5.h
@@ -39,14 +39,14 @@
 
 #define MBEDTLS_ERR_MD5_HW_ACCEL_FAILED                   -0x002F  /**< MD5 hardware accelerator failed */
 
-#if !defined(MBEDTLS_MD5_ALT)
-// Regular implementation
-//
-
 #ifdef __cplusplus
 extern "C" {
 #endif
 
+#if !defined(MBEDTLS_MD5_ALT)
+// Regular implementation
+//
+
 /**
  * \brief          MD5 context structure
  *
@@ -63,6 +63,10 @@
 }
 mbedtls_md5_context;
 
+#else  /* MBEDTLS_MD5_ALT */
+#include "md5_alt.h"
+#endif /* MBEDTLS_MD5_ALT */
+
 /**
  * \brief          Initialize MD5 context
  *
@@ -238,18 +242,6 @@
 #undef MBEDTLS_DEPRECATED
 #endif /* !MBEDTLS_DEPRECATED_REMOVED */
 
-#ifdef __cplusplus
-}
-#endif
-
-#else  /* MBEDTLS_MD5_ALT */
-#include "md5_alt.h"
-#endif /* MBEDTLS_MD5_ALT */
-
-#ifdef __cplusplus
-extern "C" {
-#endif
-
 /**
  * \brief          Output = MD5( input buffer )
  *
diff --git a/include/mbedtls/ripemd160.h b/include/mbedtls/ripemd160.h
index 3a8b50a..a0dac0c 100644
--- a/include/mbedtls/ripemd160.h
+++ b/include/mbedtls/ripemd160.h
@@ -35,14 +35,14 @@
 
 #define MBEDTLS_ERR_RIPEMD160_HW_ACCEL_FAILED             -0x0031  /**< RIPEMD160 hardware accelerator failed */
 
-#if !defined(MBEDTLS_RIPEMD160_ALT)
-// Regular implementation
-//
-
 #ifdef __cplusplus
 extern "C" {
 #endif
 
+#if !defined(MBEDTLS_RIPEMD160_ALT)
+// Regular implementation
+//
+
 /**
  * \brief          RIPEMD-160 context structure
  */
@@ -54,6 +54,10 @@
 }
 mbedtls_ripemd160_context;
 
+#else  /* MBEDTLS_RIPEMD160_ALT */
+#include "ripemd160.h"
+#endif /* MBEDTLS_RIPEMD160_ALT */
+
 /**
  * \brief          Initialize RIPEMD-160 context
  *
@@ -178,18 +182,6 @@
 #undef MBEDTLS_DEPRECATED
 #endif /* !MBEDTLS_DEPRECATED_REMOVED */
 
-#ifdef __cplusplus
-}
-#endif
-
-#else  /* MBEDTLS_RIPEMD160_ALT */
-#include "ripemd160_alt.h"
-#endif /* MBEDTLS_RIPEMD160_ALT */
-
-#ifdef __cplusplus
-extern "C" {
-#endif
-
 /**
  * \brief          Output = RIPEMD-160( input buffer )
  *
diff --git a/include/mbedtls/rsa.h b/include/mbedtls/rsa.h
index f8b8965..df6e3e5 100644
--- a/include/mbedtls/rsa.h
+++ b/include/mbedtls/rsa.h
@@ -77,14 +77,14 @@
  * eg for alternative (PKCS#11) RSA implemenations in the PK layers.
  */
 
-#if !defined(MBEDTLS_RSA_ALT)
-// Regular implementation
-//
-
 #ifdef __cplusplus
 extern "C" {
 #endif
 
+#if !defined(MBEDTLS_RSA_ALT)
+// Regular implementation
+//
+
 /**
  * \brief   The RSA context structure.
  *
@@ -129,6 +129,10 @@
 }
 mbedtls_rsa_context;
 
+#else  /* MBEDTLS_RSA_ALT */
+#include "rsa_alt.h"
+#endif /* MBEDTLS_RSA_ALT */
+
 /**
  * \brief          This function initializes an RSA context.
  *
@@ -1112,18 +1116,6 @@
  */
 void mbedtls_rsa_free( mbedtls_rsa_context *ctx );
 
-#ifdef __cplusplus
-}
-#endif
-
-#else  /* MBEDTLS_RSA_ALT */
-#include "rsa_alt.h"
-#endif /* MBEDTLS_RSA_ALT */
-
-#ifdef __cplusplus
-extern "C" {
-#endif
-
 /**
  * \brief          The RSA checkup routine.
  *
diff --git a/include/mbedtls/sha1.h b/include/mbedtls/sha1.h
index eec3f95..8f805fb 100644
--- a/include/mbedtls/sha1.h
+++ b/include/mbedtls/sha1.h
@@ -42,14 +42,14 @@
 
 #define MBEDTLS_ERR_SHA1_HW_ACCEL_FAILED                  -0x0035  /**< SHA-1 hardware accelerator failed */
 
-#if !defined(MBEDTLS_SHA1_ALT)
-// Regular implementation
-//
-
 #ifdef __cplusplus
 extern "C" {
 #endif
 
+#if !defined(MBEDTLS_SHA1_ALT)
+// Regular implementation
+//
+
 /**
  * \brief          The SHA-1 context structure.
  *
@@ -66,6 +66,10 @@
 }
 mbedtls_sha1_context;
 
+#else  /* MBEDTLS_SHA1_ALT */
+#include "sha1_alt.h"
+#endif /* MBEDTLS_SHA1_ALT */
+
 /**
  * \brief          This function initializes a SHA-1 context.
  *
@@ -243,18 +247,6 @@
 #undef MBEDTLS_DEPRECATED
 #endif /* !MBEDTLS_DEPRECATED_REMOVED */
 
-#ifdef __cplusplus
-}
-#endif
-
-#else  /* MBEDTLS_SHA1_ALT */
-#include "sha1_alt.h"
-#endif /* MBEDTLS_SHA1_ALT */
-
-#ifdef __cplusplus
-extern "C" {
-#endif
-
 /**
  * \brief          This function calculates the SHA-1 checksum of a buffer.
  *
diff --git a/include/mbedtls/sha256.h b/include/mbedtls/sha256.h
index c4465e5..adf31a8 100644
--- a/include/mbedtls/sha256.h
+++ b/include/mbedtls/sha256.h
@@ -38,14 +38,14 @@
 
 #define MBEDTLS_ERR_SHA256_HW_ACCEL_FAILED                -0x0037  /**< SHA-256 hardware accelerator failed */
 
-#if !defined(MBEDTLS_SHA256_ALT)
-// Regular implementation
-//
-
 #ifdef __cplusplus
 extern "C" {
 #endif
 
+#if !defined(MBEDTLS_SHA256_ALT)
+// Regular implementation
+//
+
 /**
  * \brief          The SHA-256 context structure.
  *
@@ -63,6 +63,10 @@
 }
 mbedtls_sha256_context;
 
+#else  /* MBEDTLS_SHA256_ALT */
+#include "sha256_alt.h"
+#endif /* MBEDTLS_SHA256_ALT */
+
 /**
  * \brief          This function initializes a SHA-256 context.
  *
@@ -198,17 +202,6 @@
 
 #undef MBEDTLS_DEPRECATED
 #endif /* !MBEDTLS_DEPRECATED_REMOVED */
-#ifdef __cplusplus
-}
-#endif
-
-#else  /* MBEDTLS_SHA256_ALT */
-#include "sha256_alt.h"
-#endif /* MBEDTLS_SHA256_ALT */
-
-#ifdef __cplusplus
-extern "C" {
-#endif
 
 /**
  * \brief          This function calculates the SHA-224 or SHA-256
diff --git a/include/mbedtls/sha512.h b/include/mbedtls/sha512.h
index ee88fcf..5bb83f4 100644
--- a/include/mbedtls/sha512.h
+++ b/include/mbedtls/sha512.h
@@ -37,14 +37,14 @@
 
 #define MBEDTLS_ERR_SHA512_HW_ACCEL_FAILED                -0x0039  /**< SHA-512 hardware accelerator failed */
 
-#if !defined(MBEDTLS_SHA512_ALT)
-// Regular implementation
-//
-
 #ifdef __cplusplus
 extern "C" {
 #endif
 
+#if !defined(MBEDTLS_SHA512_ALT)
+// Regular implementation
+//
+
 /**
  * \brief          The SHA-512 context structure.
  *
@@ -62,6 +62,10 @@
 }
 mbedtls_sha512_context;
 
+#else  /* MBEDTLS_SHA512_ALT */
+#include "sha512_alt.h"
+#endif /* MBEDTLS_SHA512_ALT */
+
 /**
  * \brief          This function initializes a SHA-512 context.
  *
@@ -197,18 +201,6 @@
 #undef MBEDTLS_DEPRECATED
 #endif /* !MBEDTLS_DEPRECATED_REMOVED */
 
-#ifdef __cplusplus
-}
-#endif
-
-#else  /* MBEDTLS_SHA512_ALT */
-#include "sha512_alt.h"
-#endif /* MBEDTLS_SHA512_ALT */
-
-#ifdef __cplusplus
-extern "C" {
-#endif
-
 /**
  * \brief          This function calculates the SHA-512 or SHA-384
  *                 checksum of a buffer.
diff --git a/include/mbedtls/timing.h b/include/mbedtls/timing.h
index 2c497bf..bbcb906 100644
--- a/include/mbedtls/timing.h
+++ b/include/mbedtls/timing.h
@@ -30,16 +30,16 @@
 #include MBEDTLS_CONFIG_FILE
 #endif
 
-#if !defined(MBEDTLS_TIMING_ALT)
-// Regular implementation
-//
-
 #include <stdint.h>
 
 #ifdef __cplusplus
 extern "C" {
 #endif
 
+#if !defined(MBEDTLS_TIMING_ALT)
+// Regular implementation
+//
+
 /**
  * \brief          timer structure
  */
@@ -58,6 +58,10 @@
     uint32_t                        fin_ms;
 } mbedtls_timing_delay_context;
 
+#else  /* MBEDTLS_TIMING_ALT */
+#include "timing_alt.h"
+#endif /* MBEDTLS_TIMING_ALT */
+
 extern volatile int mbedtls_timing_alarmed;
 
 /**
@@ -133,18 +137,6 @@
  */
 int mbedtls_timing_get_delay( void *data );
 
-#ifdef __cplusplus
-}
-#endif
-
-#else  /* MBEDTLS_TIMING_ALT */
-#include "timing_alt.h"
-#endif /* MBEDTLS_TIMING_ALT */
-
-#ifdef __cplusplus
-extern "C" {
-#endif
-
 #if defined(MBEDTLS_SELF_TEST)
 /**
  * \brief          Checkup routine
diff --git a/include/mbedtls/xtea.h b/include/mbedtls/xtea.h
index 34ccee3..8df708a 100644
--- a/include/mbedtls/xtea.h
+++ b/include/mbedtls/xtea.h
@@ -39,14 +39,14 @@
 #define MBEDTLS_ERR_XTEA_INVALID_INPUT_LENGTH             -0x0028  /**< The data input has an invalid length. */
 #define MBEDTLS_ERR_XTEA_HW_ACCEL_FAILED                  -0x0029  /**< XTEA hardware accelerator failed. */
 
-#if !defined(MBEDTLS_XTEA_ALT)
-// Regular implementation
-//
-
 #ifdef __cplusplus
 extern "C" {
 #endif
 
+#if !defined(MBEDTLS_XTEA_ALT)
+// Regular implementation
+//
+
 /**
  * \brief          XTEA context structure
  */
@@ -56,6 +56,10 @@
 }
 mbedtls_xtea_context;
 
+#else  /* MBEDTLS_XTEA_ALT */
+#include "xtea_alt.h"
+#endif /* MBEDTLS_XTEA_ALT */
+
 /**
  * \brief          Initialize XTEA context
  *
@@ -115,18 +119,6 @@
                     unsigned char *output);
 #endif /* MBEDTLS_CIPHER_MODE_CBC */
 
-#ifdef __cplusplus
-}
-#endif
-
-#else  /* MBEDTLS_XTEA_ALT */
-#include "xtea_alt.h"
-#endif /* MBEDTLS_XTEA_ALT */
-
-#ifdef __cplusplus
-extern "C" {
-#endif
-
 /**
  * \brief          Checkup routine
  *
diff --git a/library/ssl_cli.c b/library/ssl_cli.c
index 738014e..7cde5b1 100644
--- a/library/ssl_cli.c
+++ b/library/ssl_cli.c
@@ -2673,10 +2673,27 @@
     buf = ssl->in_msg;
 
     /* certificate_types */
+    if( ssl->in_hslen <= mbedtls_ssl_hs_hdr_len( ssl ) )
+    {
+        MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad certificate request message" ) );
+        mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                        MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
+        return( MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE_REQUEST );
+    }
     cert_type_len = buf[mbedtls_ssl_hs_hdr_len( ssl )];
     n = cert_type_len;
 
-    if( ssl->in_hslen < mbedtls_ssl_hs_hdr_len( ssl ) + 2 + n )
+    /*
+     * In the subsequent code there are two paths that read from buf:
+     *     * the length of the signature algorithms field (if minor version of
+     *       SSL is 3),
+     *     * distinguished name length otherwise.
+     * Both reach at most the index:
+     *    ...hdr_len + 2 + n,
+     * therefore the buffer length at this point must be greater than that
+     * regardless of the actual code path.
+     */
+    if( ssl->in_hslen <= mbedtls_ssl_hs_hdr_len( ssl ) + 2 + n )
     {
         MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad certificate request message" ) );
         mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
@@ -2691,9 +2708,32 @@
         size_t sig_alg_len = ( ( buf[mbedtls_ssl_hs_hdr_len( ssl ) + 1 + n] <<  8 )
                              | ( buf[mbedtls_ssl_hs_hdr_len( ssl ) + 2 + n]       ) );
 #if defined(MBEDTLS_DEBUG_C)
-        unsigned char* sig_alg = buf + mbedtls_ssl_hs_hdr_len( ssl ) + 3 + n;
+        unsigned char* sig_alg;
         size_t i;
+#endif
 
+        /*
+         * The furthest access in buf is in the loop few lines below:
+         *     sig_alg[i + 1],
+         * where:
+         *     sig_alg = buf + ...hdr_len + 3 + n,
+         *     max(i) = sig_alg_len - 1.
+         * Therefore the furthest access is:
+         *     buf[...hdr_len + 3 + n + sig_alg_len - 1 + 1],
+         * which reduces to:
+         *     buf[...hdr_len + 3 + n + sig_alg_len],
+         * which is one less than we need the buf to be.
+         */
+        if( ssl->in_hslen <= mbedtls_ssl_hs_hdr_len( ssl ) + 3 + n + sig_alg_len )
+        {
+            MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad certificate request message" ) );
+            mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+                                            MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
+            return( MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE_REQUEST );
+        }
+
+#if defined(MBEDTLS_DEBUG_C)
+        sig_alg = buf + mbedtls_ssl_hs_hdr_len( ssl ) + 3 + n;
         for( i = 0; i < sig_alg_len; i += 2 )
         {
             MBEDTLS_SSL_DEBUG_MSG( 3, ( "Supported Signature Algorithm found: %d"
@@ -2702,14 +2742,6 @@
 #endif
 
         n += 2 + sig_alg_len;
-
-        if( ssl->in_hslen < mbedtls_ssl_hs_hdr_len( ssl ) + 2 + n )
-        {
-            MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad certificate request message" ) );
-            mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
-                                            MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
-            return( MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE_REQUEST );
-        }
     }
 #endif /* MBEDTLS_SSL_PROTO_TLS1_2 */